Piston



Patented July 1, 1930 UNITED STATES PATENT OFFICE MELBOURNE A. BEGKMANN, F CINCINNATI, OHIO, ASSIGNOR TO HARRY J. HATER,

0F CINCINNATI, OHIO PISTON 1.

Application filed. June 7,1929. Serial No. 369,130.

My invention relates to improvements in pistons and more particularly to pistons adapted for use in internal combustion engines.

An important object of my nventlon is the provision of a piston capable of being formed from light weight material such as alum num, aluminum alloys, magnesium and similar metals in which the undesirable expansion of the piston caused by the relatively high thermal expansion ratio of the light weight material is rendered comparatively inefiective for all practical purposes.

A ,further object of my invention is the 7 production of a piston so constructed that the heat of combustion, which causes u nde sirable expansion of the piston skirt. is so diverted and impeded in the" course of its transmission from the head of the piston to its skirt, that itsinfiuence upon-the skirt of the piston is reduced to a minimum.

Another object of my invention is to produce a piston, both thrust surfaces of which will be in constant contact with the surface of the cylinder Walls.

A further object of my invention is to control expansion of the piston so that it will work efficiently at all operating temperatures.

Other objects and advantages of my invention will be apparent during the course of form a part of this specification and wherein like characters of reference denote like or corresponding parts throughout the same.

Figurel is a front elevation oi my improved piston,

Figure 2 is a central vertical set-i ion taken ml the line'22 of Figure 1,

, not shown.

Figure 3 is a central vertical section taken pending rim 11 provided with a series of ring grooves 12 to receive suitable packing rings separated from the head and rim 11 by a circumferentially extending opening 14. The piston skirt'is relieved by being completely cut away at diametrically opposite points, and said cutaway portions 15 extend from points spaced from the bottom of the skirt to the opening 14.

Piston pin receiving hubs or bosses 16 are arranged in the. cutaway portions 15 adjacent the centers thereof and are provided with the usual bores 17. The bosses 16 are connected to the portions of the skirt at the sides of the cutaway portions by horizontal or transverse struts 18 arranged above the centers of the'bosses 16. Vertical struts 19 connect the bosses 16 with the portions of the skirt at the bottom of the cutaway portions 15 and are arranged centrally of the cutaway portions and of the bosses. The struts 1 8 and '19 from T-shaped'connections between the bosses and the piston skirt, with the bosses arranged at the junctures of the arms of the T,

The inner ends of the bosses 16 are connected to the head of the piston by means of vertically extending struts arranged centrally of the cutaway portions and outwardly offset at their upper ends to join the head.

The skirt 13 of the piston is.

Suitable reinforcing ribs 21 connect the inner portions of the bosses 16 with the head of the piston and extend down the centers of the struts 20. The struts 20 extend a short distance below the bosses 16 and connect with transverse struts 22 which are joined at their ends to the sides of the piston skirt adjacent the lower ends of the cutaway portions. The struts 2O merge into encircling flanges 23 on the bosses 16 and together with the struts 22 form inverted T- shaped connections between the head, piston pin bosses, and skirt.

It willbe seen, then, that the hubs 16 are joined at their outer ends to the skirt by the struts 18 and 19, and joined attheir inner ends to the head and skirt by the struts and 22. At a suitable position between the outer struts 18 and 19 and the inner struts 20 there is an opening 24 dividing the inner end of each hub from the outer end thereof, and said opening 2 L may be out after the piston is cast, but is preferably cast with the piston. lVhen cast with the piston, the opening 24 is formed slightly wider at its lower end than at its upper end to facilitate removal of the core member therefrom. The hubs 16 are consequently separated by the opening 24 into spaced inner and outer portions, the outer portions being integrally connected with the studs 18 and 19 and the inner portions of the hubs being integrally connected with the struts 20 and 22, there being no direct connection between the struts 18 and 19 and the struts 20 and 22, or between the separated portions of the hubs.

The struts 18 and 19 are, therefore, independent of the struts 20 and 22, and heat passing from the head 10 through the struts 20 will not be conducted to the struts 18 and 19 and the adjoining skirt portions.

The non-thrust side of the piston skirt is provided with a vertical slit 25 extending from the bottom of the skirt to the opening 14 which separates the head from the skirt, and the thrust side of the skirt is unbroken. A substantially continuous annular bearing surface is, therefore, formed adjacent the bottom of the skirt and is unbroken except for the single slit 25. The inner portion of the skirt adjacent the slit 25 is provided with reinforcements 26 which parallel the slit and strengthen the separated portions of the skirt. The reinforcement 26 is preferably wider at the top than at the bottom to facilitate the removal of the core from the mold'at'tcr the piston is cast. hile the slit 25 completely separates the nonthrust side of theskirt, the arrangement of the transverse struts 1S and 22 is sutlicient to hold the separated portions of the skirt in position.

in the operation of my improved piston, the head portion is subjected to dircctheat generated by the explosion of gases in the combustion chamber, and this heat is condn'cted'away through the integrally conncctml struts 20 and through the surrounding metal of the cylinder. The struts 20 are the only portions of the piston having direct conmotion with the head of the piston, and the only path by which the heat may be conducted to the piston skirt. The heat is so reduced when itreaches the bottom of the skirt that very little is transmitted upwardly to the side walls of the skirt, and is, therefore, comparatively ineffective due to the long and circuitous route which it must travel.

sorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. A piston comprising a head and skirt, said skirt being spaced from said head by a circumferentially extending opening. means .connecting said head and skirt, said skirt being provided on its nonthrust side with a vertical slit: extending from the bottom of the skirt to the opening separating the head from the skirt. and a reinforcement extending substantially throughout the length of said slit on the interior of the piston skirt, said reinforcement tapering towards the lower end of the skirt. whereby the reinforcement is wider at its upper end than at its lower end.

2. A piston comprising a head, a skirt spaced from said head by a circm-nferentiallv extending opening, said skirt being provided with diametrically opposed cutaway portions, piston pin hubs arranged in said cutaway portions. substantially T-shaped struts connecting the outer ends of said hubs with the portions of the skirt at the sides and bottom of said cutaway portions, and substantially inverted T-shaped struts connecting the inner ends of the hubs with the head and skirt. said hubs being split between the T-shapcd struts and the inverted T-shapcd struts whereby the hubslare each divided into spaced portions. one portion connected to the T-shaped strut and the other portion connected to the inverted T-shaped strut.

3. A piston comprising a head, a skirt spaced from said head by a circumferentially extending opening. said skirt being provided with a cutaway portion spaced from the bottom of the skirt and extending into said circiunfercn'iially extending opening. a piston 11 pin hub arranged in said cutaway portion n substantially "r shaped strut connecting tllc outer end of said hub with the portions of the skirt at the sides and bottom of said cutaway portion, and a substantially inverted T-shaped strut connecting the inner end of said hubwith the head and skirt, said hub being split between the T-shaped strut and theinverted T-shaped strut, whereby the hub is divided into spaced portions, one portion connected to the T-shaped strut and the other portion. connected to the inverted T-shaped strut.

4. A piston comprising a head and skirt,

Y said skirt being separated from the head by a posed cutaway portions extending into the circumferential opening, piston pin hubs arranged in said cutaway portions, struts connecting the outer ends of the hubs with portions of the skirt at the sides and bottoms of 70 the cutaway portions, and struts connecting the inner ends of the hubs with the head and the skirt, said hubs being split between the struts whereby the hubs are divided into spaced portions, the separated portions of the hubs and their associated struts being independent of one another.

In testimony whereof I alfix my signature.

- MELBOURNE A. BEOKMANN.

' said hub being split between the two sets of struts whereby the hub is divided into spaced portions, the separated portions of the hub and their associated struts being independent of one another.

5. A piston comprising a head and skirt, said skirt being separated from the head by a circumferentially extending opening, said skirt being provided with diametrically opposed cutaway portions, piston pin hubs arranged in said cutaway portions, substantially T-shaped struts connecting the outer ends of the hubs with the portions of the skirt at the sides and bottoms of the cutawayportions,and substantially inverted T-shaped struts connecting the inner ends of the hubs-with the head and the skirt, said hubs being split between the T-shaped struts and the inverted T-shaped struts, whereby the hubs are divided 40 into spaced portions, the non-thrust side of the skirt being provided with a vertically arranged slit extending from the bottom of the skirt to the circumferential opening, and

a reinforcement arranged on the inside of said skirt adjacent said vertical slit, the separated portions of the skirt being braced by said struts. I

6. A piston comprising a head and skirt,

said skirt being provided with a cutaway portion extending from a point spaced from the bottom of the skirt to the head, a piston pin hub arranged in said cutaway portion, struts connecting the outer ends of the hubs with the portions of the skirt at the sides and bottom of the cutaway portion, and struts connecting the inner end of the piston pin hub with the head and skirt, said hub being split between the two sets of struts whereby the hub is divided into spaced portions, the separated portions of the hub and their associated struts being independent of one another.

7. A piston comprising a head and skirt, said skirt being separated from the head by'a circumferentially extending opening, said skirt being provided with diametrically op- 

